I’m installing a new 50 Amp subpanel for a kitchen and laundry room remodel and need to run 6/3 Romex back to it. I’m not running EMT because the walls will be covered and I thought this would be easier. Can I attach the 6/3 Romex directly to perpendicular joist or do I need to go through the joists as with smaller wire? The Code Check book was unclear on this. Also, in general, what are the codes and restrictions for drilling boring top plates? The house has one story over the garage, if that matters. Lastly, can I run two 14/2 or two 12/2 wires through one 5/8 hole, either in a joist or top plate? Code Check says nothing about top plates, just joists, girders, and studs.
Thanks much for any help.